More information on Low Friction Rings & Blocks:

The lightweight alternative to a block, low friction rings are machined of ultra-smooth aluminum. Flexible for use in tons of applications with no moving parts and no maintenance. Another great block alternative found in this category are the Ronstan's shock blocks. The come in a variety of colors and can be used virtually anywhere on a dinghy you might use a block. Antal also makes a great option: low friction rings that can also be purchased with dyneema loop attachments.